Role of the coat (CP), movement (MP) and 2b proteins of parietaria motte virus (PMoV) as pathogen determinants in Nicotiana benthamiana plants
2025
Martínez, C. | López, C. | Pallás, Vicente | Aparicio, Frederic | Galipienso, Luis
Parietaria mottle virus (genus Ilarvirus, family Bromoviridae) is an emerging virus infecting tomato and pepper crops in the Mediterranean basin. PMoV has a segmented single-stranded positivesense RNA genome encoding two replicase subunits (p1 and p2), the 2b, the movement (MP) and coat (CP) proteins. Mechanisms underlying the disease development are poorly understood in most virusplant pathosystems. For this purpose, we have investigated the role played by the PMoV CP, MP, and 2b as pathogen determinants in the experimental host Nicotiana benthamiana. Transient expression of the PMoV proteins by using the PVX cDNA viral vector pGR107 showed that all of them enhanced the PVXinduced symptoms in N. benthamiana agroinfiltrated plants, but with different degrees. CP was associated with strong symptoms of systemic necrosis typical of hypersensitive host response (HR), mosaic leaf deformation, and plant stunting. 2b and MP were associated with mild mosaic and leaf deformation. However, movement complementation assays of a viral vector based on turnip crinkle virus sequence expressing GFP (pTCV-GFP) revealed that none of these PMoV proteins could suppress the post-transcriptional gene silencing (PTGS) host defense mechanism. Additional assays of systemic RNA silencing in transgenic N. benthamiana 16c plants expressing the green fluorescent protein (GFP) confirmed that PMoV 2b, unlike other ilarviruses, was not a PTGS suppressor. Results obtained here are discussed and compared with those of other virus-plant pathosystems
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